"We don't know very much about what the risk factors are for chronic inflammatory diseases like psoriasis," said Dr. Joel Gelfand, a dermatologist at the University of Pennsylvania in Philadelphia, who was not involved in the new research.

"This study points in a potentially new direction for a potential risk factor that - in theory - could be modified and thus lower the risk of psoriasis in the future," he told Reuters Health. "That being said, this finding needs to be confirmed by more-rigorous, more-controlled studies to determine if the findings are real."

Psoriasis is thought to be caused by a mistaken immune reaction directed at the body's own cells, leading to inflamed patches of red, scaly skin.

It's not the first time the condition has been linked to other health problems. Earlier this year, a study of people evaluated for heart disease found 84 percent of patients with psoriasis had coronary artery disease, compared to 75 percent of patients without the skin condition. (See Reuters Health article from January 10, 2012.)

Oral health has also been tied to other conditions, with two studies from this year finding links to heart disease and dementia. (See Reuters Health articles from April 19 and 21, 2012.)

But until now only one other study had looked at the link between psoriasis and chronic periodontitis, the advanced stage of the gum disease gingivitis.

For the new research, published in the British Journal of Dermatology, Dr. Joseph J. Keller from Taipei Medical University and his colleague turned to a database of Taiwan's national health system.

They identified 115,365 people with gum disease, and then selected the same number of people without the condition. The researchers then looked through the database to see how many people in each group developed gum disease over the next five years.

In the group with gum disease, 1,082 developed psoriasis, while 706 did in the comparison group. That works out to about 1.9 in 1,000 people versus 1.2 in 1,000, respectively.

According to the researchers, their findings may challenge some of what is known about psoriasis's underlying cause, but they caution their study has some limitations.

Specifically, they were not able to account for certain factors that could have played a role, such as cigarette smoking. And until the findings are confirmed, Gelfand said, people with gum disease should not be alarmed.

SOURCE: http://bit.ly/PWyRZl British Journal of Dermatology, online September 27, 2012.

NEW YORK (Reuters Health) - Older adults who get thorough dental cleanings may be somewhat less likely to have a heart attack or stroke than their peers who are less careful about oral hygiene, a new study suggests.